In the near future an increasing demands for communication over wide distances, especially for example between continents will be needed. Hence, infrastructures, like sea cables and connectors linking sea cables and modules, e.g. subsea modules, like transformers, pumps etc., that are located and operated error proof subsea will be essential. To isolate the internals and the electrical contacts of the female part of such a connector from salt water and debris as well as to support the mating of the female part with a male part of the connector. A receiving chamber of the female part is filled with an insulation lubricant. During the mate or due to thermal variances a part of the lubricant will be displaced by the male part and will be pushed into a volume compensator. Also, a chamber in which the cable is terminated to the connector, commonly termed the ‘gland’, is a compensated unit that too will suffer from the effects of expansion due to temperature and pressure variances. It is known to integrate metallic bellows in the connector to compensate for pressure or thermal expansion and contraction. Such a metal bellows must be for example welded to structures of the female part. These welds are often weak points causing sea water to enter the receiving chamber and acting detrimental on connector internals. Moreover, current compensation systems utilise elastomeric diaphragms as a barrier and as a means of pressure and thermal compensation between sea water and connector insulation lubricant (oil, silicone gel etc.). Although elastomeric diaphragms have been seen to be adequate, they are known to permeate sea water over time under extreme circumstances. This can result in failure of the connector.
GB1379525 describes a two part coupling in which one part has a cavity with an end closed by a diaphragm and pin contacts from the other part can penetrate the diaphragm during coupling.
U.S. Pat. No. 5,738,535 describes an underwater electrical or optical connector having a plug unit and a receptacle unit, each having a seal to seal bores in each unit until two parts are mated together.